1. Field
This disclosure relates generally to memories, and more specifically, to non-volatile memories having a dynamically adjustable soft program verify voltage level.
2. Related Art
A flash memory cell is a type of non-volatile memory (NVM) cell that stores charge on a floating gate. The amount of charge on the floating gate determines a threshold voltage (Vt) of the cell, hence the logic state stored by the cell. Each time the cell is programmed or erased, electrons are moved to or from the floating gate. The floating gate is electrically isolated so that charge is stored indefinitely. However, as geometries continue to scale down, the gm degradation (where gm=ΔIds/ΔVgs) of a flash bitcell with increasing program and erase cycling becomes more significant causing a need to better manage column leakage throughout the lifetime of the part. To address this gm degradation, soft program has been introduced to tighten the Vt distribution of erased cells. However, this soft programming increases erase times for the flash memory thus resulting in decreased system performance.